已知 x(x-1)-(x2-y)=-2,求2分之x2+y2-
已知X2+Y2+8X+6Y+25=0 求代数式X2++XY+4Y2分之X2-4Y2 减X+2Y分之X的值
已知实数x.y满足(x2+y2)(x2+y2-1)=2,求x2+y2的值
已知圆x2+y2-2x-2y+1=0求x2+y2的最大值
已知2x=3y,求xy/(x2+y2)-y2/(x2-y2)的值
已知x(x-1)-(x2-y)=-3,求x2+y2-2xy的值
已知x-y+1,X2+Y2=25 求(x+y)2和x2-xy+y2的值
已知x,y为实数,且(x2 +y2)(x2 +y2+2)=3.求x2 +y2的值
已知方程x2 +y2+4x-2y-4=0,求x2 +y2的最大值
已知x2+y2+4x-6y+13=0 求x2-2x\x2+3y2
已知[(x2+y2)-(x-y)2+2y(x-y)]÷4y=1,求4x/4x2-4y2-1/2x+y的值,
已知x2+4y2+x2y2-6xy+1=0,求 x4-y4/2x-y 乘 2xy-y2/xy-y2 除以(x2+y2/x
已知实数x,y满足x2+y2=1,求y+2x+1